Pavel Martyshkin

Project of rotating carbon high-power neutron target, conceptual design

The project of high intense neutron source for SPES project in LNL, Legnaro has been developed. The source is based on rotating carbon target. The target is bombarded by deuteron beam with energy 20 MeV, diameter 1 cm, average power 100 kW, and cooled by its thermal radiation. The source can produce up to 10/sup 14/ neutron per second with energy within a range of several MeV and has lifetime of about a thousand hours.

Electron-Positron Pre-Injector of VEPP-5 Complex

The work on the construction of the ee factory complex is in progress at Budker INP. For an e ective operation of these machines the injector complex is designed. It consists of a preinjector for the production of e and e bunches and their acceleration up to an energy of 510 MeV, and a damping ring. This paper presents the general scheme and the current status of the preinjector.

Status of work on the VÉPP-5 injection complex

The VÉPP-5 injection complex under construction at the Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of Sciences is a powerful source of intense electron and positron bunches at 510 MeV, which covers all needs of the electron–positron colliding beam setups currently operating and under construction at the Institute of Nuclear Physics. The complex includes a 285 MeV linear electron accelerator, a 510 MeV linear positron accelerator, and an accumulator–cooler with beam injection and ejection channels. Intense work on the design, assembly, and tuning of the linear electron accelerator has been conducted in the last 2 yr. As a result, by August 2002 the linear electron accelerator was put into operation with all standard subsystems. By this time, the isochronous achromatic turning of the electron beam, a system for converting electrons into positrons, and the first accelerating structure of the linear positron accelerator were assembled and put into operation. All this made it possible to accelerate the positron beam up to 75 MeV. Preliminary results of tests of the linear accelerators are presented.

Experimental Facility for E-Beam Irradiation Test of Prototype IF Target in RISP

Nowadays project RISP is developed in IBS, Daejeon. One of the main project device is graphite target system for production of rare isotopes by means of the in-flight fragmentation (IF) technique. The power inside the target system deposited by the primary beam with energy of 200 MeV/u is estimated to be around 100 kW. The target represents rotating multi-slice graphite disc cooled by thermal radiation. Necessary step of the target development is integrated test of target prototype under high power electron beam modelling real energy deposit into target. This test is planned to be held in BINP, Novosibirsk, with the use of ELV-6 accelerator. This paper presents the design of experimental facility as well as experimental program of test. Specifications of electron beam (energy close to 800 keV, size ~ 1mm, total power 30-40 kW) are discussed. Parameters and design of basic devices and systems of facility are described. INTRODUCTION At the present time in IBS (Institute of Basic Since, Daejeon, Korea) the RISP (Rare Isotope Science Project) is carried out [1,2]. Project purposes are production and investigation of new isotopes of chemical elements for fundamental research. In RISP, in particular, the In Flight (IF) fragmentation method of isotope production, wherein the heavy-ion beam energy is up to 200 MeV/u and diameter is ~1 mm cracks on the solid-state target (stripper), is realized [3]. IF target represented the rotating multi-layer thin graphite disk in vacuum with cooling by its own thermal radiation [4]. Its peculiarity is high working temperature (up to 1900 °C) and temperature gradient. Presented paper describes planned testing of multilayer target prototype under the high-power in vacuum. EXPERIMENTAL PROGRAM Goal of prototype testing is experimental check of general parts of IF target under conditions as close as possible to the operational ones. Test of prototype is envisaged to clarify a series of technical and physical problems which arise designing the target, including: • to clear up the possibility of multi-layer target construction to dissipate the beam power, its resistance to thermal and mechanical stress; • to test the cooling panels aimed to accept and remove the heat power, heat transfer balance; • to check up the calculations of prototype operation conditions, in particular, the temperature fields of front and rear target layers; • to test the control, measurement and protection methods proposed for the target subsystems design. Heavy-ion beam will be modelled by the ebeam of ELV-6 accelerator [5-6] with diameter down to ~1 mm, energy 800 keV (minimum possible) and power up to 40 kW. Maximum beam power will be limited by the graphite beam dump ability to utilize the ebeam energy deposit [7]. Figure 1: Experimental device. 1 – rotating target, 2 – rotary motion unit, 3 – cooling panels, 4 – protective diaphragm, 5 – graphite cone beam dump, 6 – protective graphite blanket, 7 – telescopic connecting tube to accelerator with beam control magnetic elements, 8 – optical ports, 9 – beam measurement plate ports. 1

High-Power High-Temperature Graphite Beam Dump for E-Beam Irradiation Test of Prototype IF Target in RISP

Nowadays project RISP is developed in IBS, Daejeon [1,2]. One of the main project device is graphite target system meant for production of rare isotopes by means of the in-flight fragmentation (IF) technique. The power inside the target system deposited by the primary beam with energy of 200 MeV/u is estimated to be around 100 kW [3]. The target represents rotating multi-slice graphite disc cooled by thermal radiation [4]. Necessary step of target development is integrated test of target prototype under high power electron beam modelling real energy deposit into target. This test is planned to be held in BINP, Novosibirsk, with the use of ELV-6 accelerator [57]. Heavy-ion beam will be modelled by the ebeam of ELV-6 accelerator with diameter down to ~1 mm and energy 800 keV (minimum possible). IF target is not full stopping target for an electron beam with energy 800 keV. Considerable part of beam energy will be not absorbed by a target material and must be deposited into special beam dump. In this paper the design of beam dump of the graphite cone geometry cooled by thermal irradiation is described. BEAM DUMP PURPOSE AND LAYOUT Beam dump is mainly purposed for utilization of electrons passed through the rotating target and removing the excess energy from experimental area. Beam dump is insulated from installation body. Simultaneously it means prevention the direct passing of high-energy electrons into metal surfaces. Moreover, it is specified using of current signal from beam dump for fast interlock unit. These tasks cause general layout of beam dump devise is shown in Fig. 1. • Graphite conical beam dump with thickness 2 mm absorbs most part passed electrons and removes its energy by the thermal irradiation. The thickness of graphite is enough for electron beam full stopping. • Cylindrical graphite blanket protects the outlet metal devices from electrons scattered with high angles. This device also is cooled by thermal irradiation. • Water beam dump and additive cooling panel removes heat by water cooling channels. Also this devices saves overheat of the different parts of installation against of direct graphite thermal irradiation. • Ceramic insulator gives possibility to measure electron beam current through graphite cone. Figure 1: Layout of beam dump: 1 – multi-slice rotating target, 2 – cooling panel, 3graphite cone beam dump, 4 – graphite blanket, 5 – water beam dump, additive cooling panel, 7 – ceramic insulator, 8 – target shaft. Main problem of beam dump development is optimization of device size and placement. First of all, beam dump must have enough large size for providing high flow of thermal irradiation without overheat of graphite more than 1900-2000 °C. In other hand, a beam dump size is limited by maximum sizes of installation: distance between target shaft and electron beam axis is ~ 10 cm. Also, operational conditions of beam dump will determine maximum possible electron beam power during experiment Principal subtasks of target development are next: • simulation of electron beam scattering and passing through rotated target, • estimation of beam dump heating, temperature and thermal stress distribution, ultimate parameters of electron beam, • estimation of heat removal by external cooling channel, • optimization of beam dump design and operational conditions, • definition of ultimate experimental regime for the next prototype test [4, 7]. SIMULATION OF ELECTRON BEAM SCATTERING Simulation of electron beam passing through the rotating target was performed by G4beamline code based on GEANT4 by means of Monte Carlo method. Main 1 2

Production of intense beams of singly charged radioactive ions

An apparatus for the production of intense beams of singly charged radioactive ions operating in on-line regime is proposed. The radioactive atoms are produced in a uranium-graphite (UC) target bombarded with neutrons. The neutron flux is generated by a graphite neutron converter, which is bombarded with protons. The atoms of the produced isotopes are ionized in the electron beam generated with the electron gun and the ions of interest are extracted in a separator. The apparatus consists of the following parts. (1) Rotating converter dissipating a substantial power of proton beam. (2) UC target placed in a graphite container at high temperature. The atoms of radioactive isotopes can be extracted with a flow of noble gas. (3) Triode electron gun with ionization channel is placed inside the solenoid forming a focusing magnetic field. The cathode of the electron gun is a spout of the graphite container. The atoms of radioactive isotopes are carried with gas flow through the spout into the electron beam. (4) ...

Project of rotating carbon high-power neutron target. Simulation of the target thermal and mechanical operation conditions

The methods and results of the calculation of the 100kW neutron target thermal and mechanical conditions are presented. Calculation is made for optimization of the target design and consists of the thermal and mechanical stress determination.